by Lucio Cadeddu

LC >
Many audiophiles and HiFi designers believe that a lot has been already
said and done in preamplifiers and power amplifiers for HiFi audio.
Not only, but there's a trend (fashion?) to re-discover old schemes and
circuits of, say, 30-40 years ago.
I believe that new ideas are always needed and that research in audio
designing should never stop and repeat itself.
May you tell our readers something about up-to-date ideas in amplifiers
designing?

KM >Everything old is new again!. I don't think that this is a new concept.
Every generation always thinks that they have invented the wheel, but
obviously they have not.
When it comes to Audio design, there are many ways
that an Engineer/Designer can generate a circuit- combinations of
technologies, devices and simply novel ways of using these devices.
If I refer to valve design, there really is absolutely nothing new - in fact,
most of the super valve preamps are nothing more that a Macintosh C33 with
upgraded parts!
Those other designs are copies of oscilloscope differential
amplifier inputs, or even basic 'buffer circuits'.
Where some of the more clever designers have deviated is to incorporate
some modern ideas, i.e. switching mode power supplies, or solid state
elements to form a sort of hybrid.
But these are legitimate designs because the components of today are
very different than those of yesteryear - which also flies in the face of
common sense, when you see designers actually 'rolling their own' capacitors
in oil. I see all this as 'fun'. There is a certain euphoria when one
transplants a technology from the 1920's -a feeling of H.G. Well's TIME
MACHINE.
There is nothing wrong with this, as there is nothing wrong with
adoring classical art AND modern art.
I still enjoy listening to Maria Callas on Edison Cylinders!
It transports me back to these simpler times.
Some up to date ideas? Well, where do I start! So that I don't bore your
readers, I suggest that they have a look at my Web Site at
www.metaxas.com.au where this is
explained in much detail.
But please note that some major changes are coming. Stay tuned.
But to distill my thoughts on design:

Get rid of capacitors. These are the most insiduous devices, and really
account for the 'transistor sound'-the sound of bad capacitors! How do we
achieve this at MAS today? Simple, we design the circuits without them! Then
when we have to use them, we use our new idea of 'decoupling capacitors'-
isolating them with a resistor so that they have a defined impedance to the
circuit.

Keep things simple and consistant. MAS was one of the first companies to
keep circuit distances very short from input to output. In our new series,
it is even shorter!

Know the 'sonic signature' of the parts you use so that you can try to
eliminate it by being a clever designer (otherwise how could excellence
Champagne be made from such awful wine -refer to my "Trip To The Grande
Marques" at www.vive.metaxas.com.au)

Know the language of music, and make sure the circuit does not get in the
way. This is new in a way because as our sensibilities improve with age, we
understand much more of the delicate nuance of music- that is why Picasso
was a better Artist at 60 than at 30.

LC >
Speaking of trends, how do you see the minimalist approach of
Japanese and French audiophiles (quickly becoming very popular
worldwide) of coupling very low power amplifiers (3-5 watts) with
super-high efficency loudspeakers?

KM >
Before I answer that, remember that it was a certain 'Gallic-Japanese'
Jean Hiraga who started this in Europe (France) through La Nouvelle Revue Du
Son. I think that this is a good trend because it is always easier to
manufacture/design a low powered amplifier which sounds exceptional than a
higher powered one.
The new IKARUS Mk5 takes full advantage of this, and you
should try to audition one and compare it directly with a single-ended
valve. You will be very surprised!
Also, I think that speakers are simply too inefficient anyway - but not at
the loud or macro-end, but the micro-end. It will improve the overall sound
of High End if the resolution at low power levels improves - this is the
natural advantage of Electrostatics, because even though traditionally they
are not efficient and not practical in the 'macro-information' sense - i.e.
really loud music, their incredible low-level retrieval allows them to
increase the dynamic range at the micro-end.
Also, all designers are starting to realise that in order to improve the
overall sound, it is not what happens at the macro-end which is important,
but the micro-end.
The noise floor, RF interference etc, have been masking this information.
As soon as you clean this end of the dynamic range - voila!
I have been doing this for years because my design tools - GOLDMUND REFERENCE
Turntables, STELLAVOX Tape Recorders with B&K microphones allowed this to be
heard.

LC >
A old wives' tale tells that 60 watts from a solid state amplifier
are not equal to 60 watts from a tube amplifier, that is to say, a vacuum
tube amplifier sounds somewhat *louder* than a transitors one, for a given
power.
What's the real story, according to your experience?

KM >
The real story is not the actual power rating, but how the amplifier reacts
with the speaker. Most 60W valve amplifiers are simply able to convey more
information at lower levels and thus appear more powerful. Also, most
solid-state amplifiers still sound awful because the designers don't
understand how to use transistors properly, and have never really heard the
sound of *reality*. I can almost say that even a bad valve amplifier can
sound 'musical', but a bad transistor amplifier sounds like 'a polished
turd'.
I have written a lot about the sound of Tubes vs Transistors at
my site.
Also, I must add, that many solid-state designers are not nearly as
fanatical when it comes to component selection. This is because it is much
easier to find normal off-the-shelf low voltage (crappy) components. High
voltage components are far more difficult to find, and so they tend to be
better made. With solid-state, bad component selection really makes the
sound 'compress' and become harsh much more easily.

LC >
Why, according to you, are the valve amplifiers all the rage today?

KM >
Valve amplifiers (single-ended etc) are the rage because the Chinese (who
are probably the biggest consumers) are making zillions of them which you can
buy for US$100!!! There is nothing wrong with this as it makes 'valves' more
accessible to more people, and hopefully some of these people will head in
my direction a few years later.
But not everyone wants to play with their valves or has the time/expertise
to do so.
Almost three years ago, I felt odd at the PENTA SHOW because I was
probably the only company demonstrating solid-state!

LC >
I believe one of the fields of HiFi audio where research and development
can seriously make huge differences is loudspeakers design.
Fancy and strange projects aside it seems that loudspeakers haven't changed
much in the last 30 years, I mean, the 90% of the market is made of conventional
dynamic speakers. Materials have changed but the approach is still the same.
How do you see the situation? Is there room for new ideas and designs?

KM >
I agree with you. But I am happy to say that a new MAS product about to be
released is our "ELECTROSTATIC RIBBON" Patent Pending. This new technology
takes electrostatics into new territory. Firstly, the "ER" is almost 6dB
more efficient than the equivalent Electrostatic, and does not have the
peculiar venetian-blind effect, which all statics have.
I cannot say more about the design except for that it really is a tremendous
improvement in this technology. And MAS will be offering elements on an OEM
basis to other manufacturers who want to develop hybrids.

LC >
One of the most Frequently Asked Questions is related to 3D stereo image
creation in standard listening rooms.
Audiophiles complain about how difficult is to create a realistic soundstage
with just two speakers and many of them are starting to look at *surround* DSP
techniques in order to get what their *stereophonic* system isn't able to
give them.
I believe two speakers are *necessary and sufficient* to create a realistic
soundstage and that the final result mainly depends on recordings and room
acoustics.
What's your opinion on this subject? What should we realistically expect from
DSP technologies? Is stereophonic reproduction come to an end?

KM >
DSP is not necessary. My entry level IKARUS Integrated amplifier with a
pair of minimonitors would dispel the notion that you cannot achieve a
holographic effect with stereo.

LC >
Mas is well known for making top quality amplifiers and preamplifiers.
Now you're making also digital electronics, loudspeakers and cables, may
you reveal some secret projects to our readers?

KM >
Some new projects which will be released in August 1997 are:

The world's first Electrostatic Ribbon.A range of OEM electrostatic
ribbons- full range panels, mid-treble panels and treble panels.Plus of
course our own hybrids using this technology.

Updated version of the EMPEROR & CZAR Full Range Electrostatic using
this patented technology.

New range of amplifiers which significantly improve upon the current
range and feature a new type of case construction- built like a 'Ferrari'
with a steel frame, and stone-dust loaded epoxy shell.

Cables which lower the noise floor dramatically, offer 100% RF and
magnetic shielding, and use the fastest copper with bandwidth of over 1
GigaHz per 1,000 metres!